TIFF in Mail app when screenshot from Firefox

[macstatic]

My wife often takes screenshots in Firefox using its built-in screenshot function, and selects "Copy" (Copy screenshot to clipboard).
If she's sending it to someone she simply goes into the Mail app, creates a new message and presses CMD-V (paste) which does exactly that (pastes the screenshot into the message). Much quicker than having to save it on to the desktop, then dragging (or selecting it with the file-selector). The problem is that the receiver gets it as a TIFF file, and as this isn't as common as other formats I'd like to use PNG instead.

So I've been trying to track down where the source of the problem comes from:

- Mail app?: the recipient gets a .TIFF attachement so this may very well be the culprit
- Firefox?: could very well be, but how do I figure this out because I never get to know the file-format when I paste it into something like TextEdit etc.

Then I did another test: on another Mac of mine I use Thunderbird for my email, so I proceeded by taking another Firefox screenshot, pasted it into a new message and there it was: a TIFF file named "PasteGraphic-1.TIFF", but confusingly when I sent it (back to myself in Thunderbird) the image was a part of the message itself and not an attachement, so I'm equally confused.
Does anyone know what's happening here, and what I need to do to change those Furefox screenshots into .PNG?

 

[kryten2]

So I've been trying to track down where the source of the problem comes from:

Seems like other people started tracking a long time ago. Info: Change Pasted Image format from Tiff to JPG How?
Data from the clipboard can be used with Image Events for file conversion, put back on the clipboard.
Info: Image Events

 

[dwig]

...
So I've been trying to track down where the source of the problem comes from:

- Mail app?: the recipient gets a .TIFF attachement so this may very well be the culprit
- Firefox?: could very well be, but how do I figure this out because I never get to know the file-format when I paste it into something like TextEdit etc.
...

It would take a Clipboard "sniffing" app to let you see what is actually in the Clipboard.

• When an app copies to the clipboard it chooses what formats to copy and whether it copies actual data or just posts an "IOU" that serves to say that "I'll post real data in this one format if and when some app chooses to paste it". This "IOU" bit allows a pasting app to offer a wide range of data formats without burdening the system with massive duplicate data.
• When a app pastes data it chooses from the available formats. Apps all have there "default" format choices. Some only support one format and can't paste if it isn't there. Most have a short ordered list of what they can paste. The best app behavior is to offer the user a Paste Special... option where a list of available and acceptable formats is presented to the user for them to choose.

While TIFF is a very standard format, but few email apps will display the format. The end user has to usually download the TIFF from the email to view it. You'll likely need to find a intermediate app to paste the TIFF data and then save as PNG.

 

[BrianBaughn]

I don't see a way in Firefox settings or on its about:config page to change the TIFF behavior.

There is at least one Firefox add-on, "Easy Screenshot", that will take screenshots in the PNG format. I'm not sure if that add-on just uses the macOS default format.

Also, if your wife is only taking screenshots of sections of the web page she could use the macOS command for saving the screenshot to the clipboard: shift-control-command-4.

The defaut format is PNG but can be changed in Terminal via:

How to Change the Default Screenshot File Format in macOS

Here's how to stop macOS from saving screenshots as PNGs, and switch to another option.

www.laptopmag.com

 

[Cyby-CyberDog]

Hmm, saving as .tiff is not really the standard setting AFAIK. Changing the screenshot format setting in Firefox is not straight forward.

To set the default screenshot file format in Firefox on MacOS, follow these steps:

1. Open Firefox and type "about:config" in the address bar.
2. Click on the "I accept the risk!" button to continue.
3. In the search bar, type "screenshot".
4. Double-click on the "extensions.screenshots.defaultFormat" preference.
5. In the dialog box that appears, enter the desired format for your screenshot file (e.g., "png", "jpeg", "bmp", etc.).
6. Click "OK" to save the changes.

Once you have set the default screenshot file format, any screenshots you take in Firefox will be saved in that format by default.

 

[BrianBaughn]

Hmm, saving as .tiff is not really the standard setting AFAIK. Changing the screenshot format setting in Firefox is not straight forward.

To set the default screenshot file format in Firefox on MacOS, follow these steps:

1. Open Firefox and type "about:config" in the address bar.
2. Click on the "I accept the risk!" button to continue.
3. In the search bar, type "screenshot".
4. Double-click on the "extensions.screenshots.defaultFormat" preference.
5. In the dialog box that appears, enter the desired format for your screenshot file (e.g., "png", "jpeg", "bmp", etc.).
6. Click "OK" to save the changes.

Once you have set the default screenshot file format, any screenshots you take in Firefox will be saved in that format by default.

In what version of Firefox are you doing that? I'm in 113.0.1 and don't see that preference in about:config.

 

[macstatic]

Same here! I initially had version 110 or something and tried it without finding "extensions.screenshots.defaultFormat", then updated Firefox to 113.0.1 and see it's still not there.
This is what I get when searching for "screenshot":

 

[BrianBaughn]

There is nothing on the internet anywhere about "extensions.screenshots.defaultFormat"…but there will be after this thread is crawled.

 

[Cyby-CyberDog]

I stand corrected, this option does not exist in the current (?) version of FireFox.

I had a second look at the question.

When you copy a screenshot in Firefox to the clipboard, on Mac OS, the default clipboard format for images is TIF, so copying a screenshot in Firefox on Mac OS results in a TIF image being stored in the clipboard.

When you save the screenshot as a file (the download option), however, Firefox uses the default file format specified in the preferences, which is usually PNG. This is why the downloaded file is a PNG image.

 

[macstatic]

I don't see a way in Firefox settings or on its about:config page to change the TIFF behavior.

There is at least one Firefox add-on, "Easy Screenshot", that will take screenshots in the PNG format. I'm not sure if that add-on just uses the macOS default format.

Also, if your wife is only taking screenshots of sections of the web page she could use the macOS command for saving the screenshot to the clipboard: shift-control-command-4.

Yes, I just learnt about this as well! I've used SHIFT-CMD-4 for years myself, but didn't know there was an option for copying to the clipboard by adding CTRL to the above. I'll try it out, and it could very well be a way to do things, although I see a few problems:

- the Firefox screenshot option is very intuitive: you get to easily select sections and there's no keyboard sequence to remember
- she's already learnt to use the above, meaning re-learning the workflow
- the Firefox screenshot option allows you to take a screenshot of an entire web page, even if it's not currently visible!

The defaut format is PNG but can be changed in Terminal via:

How to Change the Default Screenshot File Format in macOS

Here's how to stop macOS from saving screenshots as PNGs, and switch to another option.

www.laptopmag.com

Thanks! That's a nice explanation.
I've been using Onyx to play around with that setting, but apparently it only changes the usual MacOS type screenshot shortcut function's file type and changes nothing regarding Firefox/Mail app.
I don't know of any "sniffer" app to determine which format Firefox saves it as, or if this is an issue with Mail app, and according to discussions I've found on the subject like here: why paste from screenshot into mail will save as tiff format
and here: Change pasted image format from TIFF to JPG how?
.... it seems like there's no definite and clear answer on this. Maybe I should try and get in touch with the Firefox developers first and see what they say.

 

[macstatic]

I stand corrected, this option does not exist in the current (?) version of FireFox.

i'm confused. What were you referring to when you wrote to look up "extensions.screenshots.defaultFormat" if not Firefox, or the current version of it?

 

[macstatic]

From my findings so far it appears that Firefox itself is the cause of the problem of creating screenshots as (rather huge) TIFF files.
I base this upon among other things that you can check what the MacOS clipboard holds/its file-type by going to the Finder, then selecting Edit-Show Clipboard. At the bottom of that window you'll see the file type.

Has anyone else looked into this and come to a different conclusion or found out more?

 

[Tagbert]

I don't see a way in Firefox settings or on its about:config page to change the TIFF behavior.

There is at least one Firefox add-on, "Easy Screenshot", that will take screenshots in the PNG format. I'm not sure if that add-on just uses the macOS default format.

Also, if your wife is only taking screenshots of sections of the web page she could use the macOS command for saving the screenshot to the clipboard: shift-control-command-4.

The defaut format is PNG but can be changed in Terminal via:

How to Change the Default Screenshot File Format in macOS

Here's how to stop macOS from saving screenshots as PNGs, and switch to another option.

www.laptopmag.com

I’ve taken a lot of screen shots directly from Firefox and it always saves the images as PNG. I’ve never seen it save a TIFF.

 

[Tagbert]

From my findings so far it appears that Firefox itself is the cause of the problem of creating screenshots as (rather huge) TIFF files.
I base this upon among other things that you can check what the MacOS clipboard holds/its file-type by going to the Finder, then selecting Edit-Show Clipboard. At the bottom of that window you'll see the file type.

Has anyone else looked into this and come to a different conclusion or found out more?

IF you take the screen shot and save it you’ll see it is a PNG. It only is seen as a TIFF when you are using Word’s paste special. If I do a screen capture and paste it into gmail, it looks like it is a png.

 

[macstatic]

I’ve taken a lot of screen shots directly from Firefox and it always saves the images as PNG. I’ve never seen it save a TIFF.

I'm not talking about taking a screenshot using MacOS (SHIFT-CMD-4 etc), which indeed saves it as a PNG file (but can be changed to default to other formats if you change the settings via Terminal or an app such as Onyx), but here I'm referring to the built-in screenshot feature in Firefox.
For taking a screenshot of a visible section in a Firefox window I could of course use the MacOS way of taking a screenshot to the clipboard (CTRL-SHIFT-CMD-4), then paste it (CMD-V) into the app you want it, which would result in a PNG file, but the built-in Firefox screenshot feature also allows you to screenshot an entire web page from top to bottom (i.e. not just the currently visible section) which is very useful.

 

[Tagbert]

I'm not talking about taking a screenshot using MacOS (SHIFT-CMD-4 etc), which indeed saves it as a PNG file (but can be changed to default to other formats if you change the settings via Terminal or an app such as Onyx), but here I'm referring to the built-in screenshot feature in Firefox.
For taking a screenshot of a visible section in a Firefox window I could of course use the MacOS way of taking a screenshot to the clipboard (CTRL-SHIFT-CMD-4), then paste it (CMD-V) into the app you want it, which would result in a PNG file, but the built-in Firefox screenshot feature also allows you to screenshot an entire web page from top to bottom (i.e. not just the currently visible section) which is very useful.

Yes, I understand the difference between the OS screen shots and the Firefox screen shot feature. The built-in screenshot feature in Firefox saves in PNG format.

I don’t use the “copy” feature of the screen-shot tool (I just save to a file and use that) but it is possible that it copies to the clipboard as a device-independent bitmap. Then the receiver may decide to acquire and encode that image differently. Word seems to prefer a TIFF, probably because it is the most flexible format but software support is pretty limited anymore.

 

[macstatic]

Yes, I understand the difference between the OS screen shots and the Firefox screen shot feature. The built-in screenshot feature in Firefox saves in PNG format.

Sorry, I meant to refer specifically to the "Copy" (copy to clipboard) option. This results in a TIFF file while choosing the "Download" (save screenshot) option indeed saves it as a PNG file.

I don’t use the “copy” feature of the screen-shot tool (I just save to a file and use that) but it is possible that it copies to the clipboard as a device-independent bitmap. Then the receiver may decide to acquire and encode that image differently. Word seems to prefer a TIFF, probably because it is the most flexible format but software support is pretty limited anymore.

Yes, I wanted to check this more extensively, but haven't found that many apps yet which can receive the clipboard contents and display which file-format the image is in.
So far I've pasted the clipboard content (after taking a Firefox screenshot and chosen "Copy") into Mail app and MacJournal: they both show the image as TIFF.
Likewise does the MacOS Finder's "Edit-"Show clipboard" menu.

 

[Honza1]

Interesting, you learn somethng new all the time...
I was never aware of Firefox screenshot feature. I just checked and my Firefox passes to clipboard TIFF when I do "copy". I surely did not change anything from default.
And preferences "extensions.screenshots.defaultFormat" does not exist in my Firefox also.